JPS61103393A - Edgeless type speaker - Google Patents

Abstract

PURPOSE:To increase a mechanical impedance by installing an extension member at the upper surface or the lower surface of the peripheral part of the flat plate type diaphragm provided with a skin material on both surfaces of the core material and forming a clearance at the section of a frame inner circumference surface. CONSTITUTION:Skin materials 12 and 13 are provided with both surfaces of a core material 11 and a flat plate type diaphragm 14 is constituted. A cylindrical bobbin 2, for which a voice coil 1 is installed, is fitted to a central part of the diaphragm 14. To the lower surface of the circumference end part of the diaphragm 14, a foaming high polymer material, for example, an extension member 16 composed of foaming urethane is fixed. For the surface in which an extension member 16 is opposite to a frame 15, the end surface processing is executed by a skin member 18 and clearance (g) is formed at the section of the frame 15. Thus, the thickness of the end surface of the diaphragm 14 becomes large, the mechanical impedance of the clearance (g) is enlarged and the speaker with a good characteristic is produced.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an edgeless speaker having a flat diaphragm.

[Conventional technology]

An edgeless speaker using a flat diaphragm has been proposed. FIG. 10 shows an example of this edgeless speaker. (1) is a voice coil, (2) is a cylindrical bobbin, and a skin material ( A core material (5) with a honeycomb structure is arranged between 3) and (4) to form a diaphragm (6), and its frame (
The end face opposite to 71 is filled with a filler (8).

[Problem that the invention seeks to solve]

In such an edgeless speaker, the gap g formed between the frame (7) and the end face of the diaphragm (6)
The mechanical impedance Zm between the frame and the end face of the diaphragm is usually given by the following equation. That is, in the above formula, Sl is the area of the diaphragm (6), and S
2 is the area of the gap g, ρ is the air density, t is the gap width, W is the thickness of the end surface of the diaphragm, and l is the length of the surface facing the frame (see FIG. 11). According to this formula, in order to increase the mechanical impedance ZII+, the width of the gap g is also reduced,
It can be seen that it is sufficient to increase the thickness W of the end face of the diaphragm.

However, due to manufacturing considerations, there is a limit to reducing the width t of the gap (t=0.5 to III is the limit). Furthermore, a method of increasing the thickness W of the diaphragm itself can be considered, but in this case, the mass of the diaphragm inevitably overlaps, resulting in a reduction in sensitivity and reproduction frequency band.

In view of the above-mentioned points, the present invention provides an edgeless speaker in which the end face of the diaphragm is treated to increase the mechanical impedance of the gap g between the frame and the end face of the diaphragm without reducing the sensitivity and reproduction frequency band. It is something to do.

[Means for solving problems]

The present invention provides an edgeless speaker having a flat diaphragm formed by covering both sides of a core material with skin materials,
At the peripheral end of the diaphragm, a gap is formed between the upper and/or lower surfaces of the diaphragm and the inner peripheral surface of the frame in parallel with the inner peripheral surface of the frame.')) A9. D, □□. 7
, Wow.

The core material of the honeycomb structure can be made of a foamed polymeric material, and the lightweight extension members can be made of a foamed polymeric material such as urethane foam or the same material as the core material. Therefore, the core material and the extension member may be formed by a combination of a honeycomb structure and a foamed polymer material, a combination of honeycomb structures, a combination of foamed polymer materials, or the like.

[Effect]

By providing a lightweight extension member that extends from the upper surface and/or lower surface of the diaphragm at the peripheral end of the flat diaphragm facing the frame, the thickness W at the end surface of the diaphragm increases, and the frame The mechanical impedance of the gap between the end faces of the diaphragm increases, and the resonance caused by the equivalent mass of air existing in the gap and the stiffness of the diaphragm can be brought to a lower frequency range.

Moreover, the thickness W is only at the peripheral edge of the diaphragm, and since this extension member is lightweight and made of foamed polymer material or the same material as the core material, there is little increase in the diaphragm mass, and the sensitivity and reproduction frequency are reduced. Bandwidth etc. is not reduced.

〔Example〕

Embodiments of an edgeless speaker according to the present invention will be described below with reference to the drawings.

FIG. 1 shows an example of an edgeless speaker according to the present invention. This speaker has a flat honeycomb structure core material (
It has a flat diaphragm (14) with skin materials (12) and (13) adhered to both sides of the diaphragm (11), and a voice coil (
A cylindrical bobbin (2) provided with 1) is attached. In this example, especially in the diaphragm (14), the back skin material (13) is formed shorter than the front skin material (12), and the lower surface of the diaphragm is attached to the peripheral end of the diaphragm facing the frame (15). An extension member (16
) to be fixed. In this case, the extension member (16) may be inserted and fixed into the core material (ll) of the honeycomb structure. The end face of the diaphragm is processed by this extension member (16).

In the example shown in Fig. 2, skin materials (12) and (13) are bonded to both sides of a core material (11) having a honeycomb structure, and the flat plate type diaphragm ( 1
In 4), an extension member (16) made of a foamed polymer material is fixed to the lower surface of the peripheral end facing the frame so that the outer surface is flush with the end surface of the diaphragm. be.

In the example shown in FIG. 3, skin materials (12) and (13) are bonded to both sides of a core material (11) having a honeycomb structure, and the bottom surface of the diaphragm is bonded to surround the end surface of the diaphragm (14) that has not been subjected to end surface treatment. This is a case in which an extension member (16) made of a foamed polymer material that has been molded in advance so as to extend further downward is fixed.

A skin material (18) may be provided on the surface of the extension member (16) facing the frame (15) in FIGS. 1 to 3 when the extension member (16) is molded.

In the example shown in FIG. 4, a core material (11') and an extension member (16) extending downward at the peripheral end are integrally molded from a foamed polymer material, and skin materials (12) and ( 13) to form a flat plate type diaphragm (14).In addition, a skin material (18) may be provided on the surface of the extension member (16) facing the frame. This integral molding using foamed polymer material can be done by a so-called in-situ foaming method in which a mold corresponding to the shape of the diaphragm is provided and the polymeric material between the skin materials is foamed, or by cutting a foamed material or by molding it. There are two methods of attaching a skin material to a molded product using a method.

In the example shown in Fig. 5, skin materials (12) and (13) are bonded to both sides of a core material (11) having a honeycomb structure, and the surface skin material (12) is lengthened and bent to form a diaphragm (14). This is a case in which an extension member (16) made of a foamed polymer material is disposed on the lower surface of the end portion so as to fix the extension part of the surface skin material (12). The extension member (16) at this time can also be molded using the two methods described above.

The example in FIG. 6 is similar to FIG. 5, but in this case, an extension member (16) made of a foamed polymer material is arranged to surround the end face of the core material (11), and a surface skin material is attached to the outer peripheral surface of the extension member (16). (12)
A place created by extending and pasting together "'"! ,−
4 Ah.

The example shown in Figure 7 is a diaphragm (1) made by bonding skin materials (12) and (13) to both sides of a core material (11) with a honeycomb structure.
An extension member (16') having the same honeycomb structure as the core material (11) is provided on the lower surface of the peripheral end of the core material (11).
) is constructed by treating the end face of the diaphragm with, for example, one foam filler using foam ink. (20
) is skin material.

On the upper and lower sides, the diaphragm has a cross-sectional shape in which the extension member (16) or (16') extends downward as shown in FIG. (16') may extend in the vertical direction. Alternatively, although not shown, a shape in which the extension member (16) or (16') extends upward is also possible.

〔Effect of the invention〕

According to the present invention described above, a lightweight extension member (16) or ( 16') is provided integrally, the diaphragm end face 0 thickness 1 becomes large.Therefore, the mechanical impedance zI11 of the gap g between the diaphragm 1 and the diaphragm end face becomes large, and the The resonance caused by the equivalent mass of air and the stiffness of the diaphragm can be brought to the lower range.

In the present invention, this extension member (16) K11(
16') is made of a lightweight material such as a foamed polymer material such as foamed urethane or the same material as the core material, so the end face treatment mass of the diaphragm can be reduced, and the sensitivity and reproduction frequency band etc. are not reduced. . Therefore, an edgeless speaker using a flat diaphragm with good characteristics can be obtained.

[BRIEF DESCRIPTION OF THE DRAWINGS] FIG. 1 is a sectional view showing one embodiment of the edgeless speaker according to the present invention, and FIGS. 2 to 7 are main parts showing other embodiments of the edgeless speaker according to the present invention. A cross-sectional view of
8 and 9 are cross-sectional views showing the cross-sectional shape of the diaphragm according to the present invention, FIG. 10 is a cross-sectional view showing an example of a conventional edgeless speaker, and FIG. 11 is a perspective view for explaining the present invention. It is. +1) is the voice coil, (2) is the cylindrical bobbin, (11)
. (11') is core material, (12), (13),
(18), (20) are skin materials, +7),
(15) is a frame, (16). (16') is an extension member. Hidemori Matsukuma Figure 1 Figure 8 Figure 9 Figure 11

Claims (1)

[Claims] A lightweight diaphragm, which extends from the upper and/or lower surfaces of the diaphragm to form a gap with the inner circumferential surface of the frame, is attached to the peripheral edge of a flat plate diaphragm made by covering both sides of a core material with skin materials. An edgeless speaker equipped with an extension member.